Alice Nunes

Morphological and haematological parameters in the Algerian mouse (Mus spretus) inhabiting an area contaminated with heavy metals.

In the present study morphological (ratio of body weight to body length, weight of internal organs) and haematological parameters (cells count, haemoglobin concentration, haematocrit, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration) were used for monitoring potential effects of metal contaminants on the Algerian mouse (Mus spretus). The study also provided the opportunity to evaluate the use of morphological and haematological characteristics as indicators of a metal stress. Data were taken from a riverside population inhabiting a heavy metal-contaminated site and compared with those collected from a reference population of the same species. With the exception of non-reproductive males, all mice weighed less in the metal-polluted site as compared to the reference site. Spleen and kidney masses were also less in contaminated mice but mean haemoglobin concentration was greater in the polluted group versus controls. Responses of mice from the polluted area may indicate physiological stress due to diminished environmental quality. Results also suggest that M. spretus may be used as an indicator in pollution monitoring.

Lichen traits responding to aridity

Summary 1. Climate change is expected to cause several impacts at the global scale, and drylands will be amongst the most affected areas. Thus, investigating how these changes will affect the composition, structure and functioning of dryland ecosystems has become a priority. From an ecological indicator point of view, several works have shown that functional diversity is better than species richness to understand ecosystem functioning or response to environmental factors. However, most of these works focus on plants, while those of other organisms remain largely unknown. Lichens are amongst the ecosystem components more sensitive to climatic changes due to several physiological and ecological characteristics. Their poikilohydric nature (therefore highly dependent on the atmosphere for water supply) and their ubiquity on terrestrial ecosystems underlie their potential as indicators of climate. Nonetheless, works specifically aiming to identify lichen functional traits that respond to aridity remain poorly explored, particularly in drylands. 2. We proposed to identify lichen functional traits and respective functional groups responding to aridity in a Mediterranean drylands ecosystem. 3. Lichen diversity was sampled in open holm oak woodlands along an aridity gradient in SW Europe (Iberian Peninsula). Lichen functional traits that could be easily identified and related to water uptake were selected to be tested: type of photobiont, growth form and reproduction strategy. 4. Lichen species composition was related to the aridity gradient. The three traits chosen were related with the community’s response to aridity, but with contrasting responses in different functional groups. More specifically crustose and fruticose lichens, isidiate species and the ones with Trentepohlia as photobiont were related to the less arid part of the gradient. Foliose species and cyanolichens, on the contrary, were associated with the most arid areas. 5. Synthesis. We were able to identify lichen traits responding to aridity. Type of photobiont was particularly responsive, with Trentepohlia and cyanobacteria functional groups, responding clearly in contrasting ways to aridity in this drylands ecosystem. This work emphasizes functional diversity role on understanding and assessing the response to environmental factors, namely to climate. It also highlights the potential use of lichen functional groups as ecological indicators of climate change.

Fertility assessment in hybrids between monobrachially homologous Rb races of the house mouse from the island of Madeira: implications for modes of chromosomal evolution

The speciation model of divergence by monobrachially homologous fusions (that is, with one arm in common) benefits from a wide conceptual acceptance, because heterozygotes between populations carrying such fusions suffer from high levels of meiotic dysfunction. The same meiotic configurations can also be generated by WART (whole-arm reciprocal translocation), rearrangements that are known to occur in mammals. Estimating the disadvantage of heterozygotes carrying monobrachially homologous fusions is required to evaluate the relevance of this mode of chromosomal evolution in diversification and speciation. House mice are an excellent study models because chromosomal races exist carrying monobrachially homologous fusions, and WARTs have been documented in this species. The fertility of heterozygote mice carrying the smallest number of monobrachially homologous fusions (that is, a chain of four chromosomes, C4) was investigated in laboratory-bred hybrids between two parapatric chromosomal races from the island of Madeira. Meiotic nondisjunction analyses and histological sections of testes showed that aneuploidy (16.7%) and germ cell death (50.9%) rates reached significantly higher mean values in hybrids than in homozygotes. In females, however, the histological analysis of ovarian follicle parameters revealed no significant differences between hybrid and homozygous individuals. Overall, the reproductive assays indicated that these C4-carrying hybrids were not sterile but showed an approximately 50% decrease in fertility compared to homozygous parental mice. Implications for modes of chromosomal evolution involving monobrachially homologous fusions are discussed.

Hepatic elemental contents and antioxidant enzyme activities in Algerian mice (Mus spretus) inhabiting a mine area in central Portugal

In this study the effects of heavy metals (manganese, iron, copper, zinc) and selenium exposure on the hepatic activity of antioxidant enzymes, superoxide dismutase (SOD) and glutathione S-transferases (GST), were appraised on a seasonal basis in Algerian mice (Mus spretus) inhabiting an active copper mine area. A reference population of the same species was considered for comparative purposes. Different patterns of seasonal variation were found in both populations for the manganese, iron and selenium hepatic concentrations and SOD activity. When the two populations were compared, iron and selenium concentrations were enhanced in mice from the polluted area. In addition, SOD activity was significantly decreased in summer in exposed mice, but no other significant changes in SOD and GST activities between sites throughout the year were recorded. However, when seasonal data within each group of mice were pooled, significant differences were found between sites for the average concentrations of manganese, iron and selenium, which are higher in the polluted site. In addition, significant differences were obtained for the average values of SOD and of GST activities, due to simultaneously higher GST values and slightly lower SOD values in the polluted site. The population from the reference site was more homogeneous for all parameters measured than the population from the polluted area. These results, in particular the higher variability in data collected from mice exposed to heavy metals and selenium, combined with the negative associations between biochemical markers and heavy metals, may suggest, despite the good adaptability of the mice to their habitat, biochemical stress due to diminished environmental quality.

Ecological impacts of atmospheric pollution and interactions with climate change in terrestrial ecosystems of the mediterranean basin: Current research and future directions

Mediterranean Basin ecosystems, their unique biodiversity, and the key services they provide are currently at risk due to air pollution and climate change, yet only a limited number of isolated and geographically-restricted studies have addressed this topic, often with contrasting results. Particularities of air pollution in this region include high O3 levels due to high air temperatures and solar radiation, the stability of air masses, and dominance of dry over wet nitrogen deposition. Moreover, the unique abiotic and biotic factors (e.g., climate, vegetation type, relevance of Saharan dust inputs) modulating the response of Mediterranean ecosystems at various spatiotemporal scales make it difficult to understand, and thus predict, the consequences of human activities that cause air pollution in the Mediterranean Basin. Therefore, there is an urgent need to implement coordinated research and experimental platforms along with wider environmental monitoring networks in the region. In particular, a robust deposition monitoring network in conjunction with modelling estimates is crucial, possibly including a set of common biomonitors (ideally cryptogams, an important component of the Mediterranean vegetation), to help refine pollutant deposition maps. Additionally, increased attention must be paid to functional diversity measures in future air pollution and climate change studies to establish the necessary link between biodiversity and the provision of ecosystem services in Mediterranean ecosystems. Through a coordinated effort, the Mediterranean scientific community can fill the above-mentioned gaps and reach a greater understanding of the mechanisms underlying the combined effects of air pollution and climate change in the Mediterranean Basin.

Mapping and assessment of forest ecosystems and their services - Applications and guidance for decision making in the framework of MAES

The aim of this report is to illustrate by means of a series of case studies the implementation of mapping and assessment of forest ecosystem services in different contexts and geographical levels. Methodological aspects, data issues, approaches, limitations, gaps and further steps for improvement are analysed for providing good practices and decision making guidance. The EU initiative on Mapping and Assessment of Ecosystems and their Services (MAES), with the support of all Member States, contributes to improve the knowledge on ecosytem services. MAES is one of the building-block initiatives supporting the EU Biodiversity Strategy to 2000.

Tracking tree canopy cover changes in space and time in High Nature Value Farmland to prioritize reforestation efforts

ABSTRACT In High Nature Value Farmland areas such as the woodlands locally known as ‘montado’, increasing tree cover is a nature-based solution to mitigate land degradation which leads to loss of productivity and increase susceptibility to climate change. In the Mediterranean dryland areas, native tree species such as Holm-oak provide important ecosystem services. Tree cover provides shadow and food for animals, contributes to soil organic matter and protects soil from erosion, increasing water infiltration and biodiversity, thus increasing woodlands’ resilience. However, Holm-oak trees are facing high mortality rates and low natural regeneration due to both environmental and anthropogenic factors, which call for reforestation actions. Yet, because of its high costs, reforestation must focus on the most degraded areas. Tracking tree canopy cover over space and time using remote-sensing techniques could allow land managers to understand which factors promote or hinder mortality, growth and regeneration at large spatial scales, and help to prioritize areas for restoration. Most studies evaluating tree cover use a space-for-time substitution, are rarely done over time, and address small areas, thus disregarding climate effects; those performing large-scale analysis (i.e. over space) of satellite images seldom provide ground-validated information. To overcome these limitations, this study uses satellite imagery to quantify spatial and temporal changes in tree cover. This was done relating normalized difference vegetation index (NDVI) to aerial photography photointerpretation, over a precipitation gradient in a Mediterranean dryland area. Dry-season NDVI was positively related with tree canopy cover changes, both over space and time. The spatial–temporal models developed here were then validated with independent data and applied over a large area to create regional maps of changes in Holm-oak canopy cover over space and time. Thus, NDVI based-data can be used in large-scale assessments of Holm-oak canopy cover. Our findings provide an important tool to improve forest management strategies, e.g. by enabling to map and quantify tree cover decline, and to prioritize areas for reforestation, thus improving ecosystem services delivery in Holm-oak woodlands, such as improving farmland productivity and resilience to climate change.

Tracking global change using lichen diversity: towards a global‐scale ecological indicator

Summary Lichens have been used to efficiently track major drivers of global change from the local to regional scale since the beginning of the industrial revolution (sulphur dioxide) to the present (nitrogen deposition and climate change). Currently, the challenge is to universalize monitoring methodologies to compare global change drivers’ simultaneous and independent effects on ecosystems and to assess the efficacy of mitigation measures. Because two protocols are now used at a continental scale North America (US) and Europe (EU), it is timely to investigate the compatibility of the interpretation of their outcomes. For the first time, we present an analytical framework to compare the interpretation of data sets coming from these methods utilizing broadly accepted biodiversity metrics, featuring a paired data set from the US Pacific Northwest. The methodologies yielded highly similar interpretation trends between response metrics: taxonomic diversity, functional diversity and community composition shifts in response to two major drivers of global change (nitrogen deposition and climate). A framework was designed to incorporate surrogates of species richness (the most commonly used empirical trend in taxonomic diversity), shifts in species composition (compositional turnover) and metrics of functional diversity (link between community shifts to effects and ecosystem structure and functioning). These metrics are essential to more thoroughly comprehend biodiversity response to global change. Its inclusion in this framework enables future cross-continental analysis of lichen biodiversity change from North America and Europe in response to global change. Future works should focus on developing independent metrics for response to global change drivers, namely climate and pollution, taking us one step closer to a lichen-based global ecological indicator.

Nutrient Addition and Drought Interact to Change the Structure and Decrease the Functional Diversity of a Mediterranean Grassland

Anthropogenic activities are increasing nutrient availability and altering precipitation regimes. This may lead to critical changes in grasslands functioning and resilience. This is particularly important for grasslands in the Mediterranean Basin that have evolved in nutrient poor soils, and where more frequent and prolonged droughts are projected to occur. However, there is limited knowledge regarding the interacting effects of multiple nutrient inputs and rainfall variability on Mediterranean grassland functional structure and diversity. We conducted a nutrient addition experiment during four contrasting precipitation years in a Mediterranean grassland. We established four treatments that varied in the number of added nutrients from no added nutrients (control), to one added nutrient (Nitrogen-N, Phosphorus-P or Potassium-K), two added nutrients, (NP, NK or PK) and three added nutrients (NPK). We assessed the effect of increasing nutrient addition in wet, normal, dry and very dry years on species functional traits at the community level. We determined the community functional structure (e.g. Community Weighted Mean, CWM) and functional diversity (e.g. Functional Dispersion, FDis) for eight key functional traits indicators of nutrient and water use strategies. We also assessed if CWM, FDis and species richness were related to the aggregate grassland functioning property, productivity. We found that CWM was affected by nutrient addition and precipitation and, for some traits, by their interaction. However, FDis of most traits was affected by precipitation. The very dry year had a negative effect on FDis of most traits (e.g. dispersal modes, nutrient uptake strategies) and interacted with three added nutrients to decrease FDis of growth-forms. Conversely, FDis of reproductive traits decreased during the wet year. Species richness and FDis were not related to grassland productivity, whereas CWM was the main determinant of grassland productivity supporting the importance of species functional traits in determining ecosystem functioning. Our results highlight drought as a critical factor determining a decrease in the functional diversity of Mediterranean grasslands. Moreover, drought can also interact with nutrient addition changing the dominance of many traits and further decreasing functional diversity. This will have important implications for ecosystem functioning and resilience in the context of global changes.